SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e99c1816c3c8f2e00206a8ecb757b4612b9614b66fb0187aca3c96ef2da3c0c' 
  AND token = '/9YbldZlOPIBBgZ1tmYrwnyCjJ4U1EjwNWrxwzi4PfU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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