SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd349e70c578851d7fda07320f14b87c03f7666f9be706f955f9082728f5e65c1' 
  AND token = 'fX1gTzEkCaZRwnB1n6iFitimUAz7bbG5aFv2s28u0pg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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