SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12c23b12f419408579870b4147d168ba6724f619134b9cb84c2461875464d907' 
  AND token = 'jX9pt1XSsTRgBt4rqlv2uYCzt/38zFpzTShgiew6Bx0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}