SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf83af8449e51f8aeef05c6f3952a0ad7ab349479b366c3fc5a4293d4788b903' 
  AND token = 'IMXJoZOGB8idvy/NLRz/jF+Atzfd6ituUFte2xRBdwI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}