SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd316bee8bd997598505f403adb1b3f028206ed561008da64981c2e5da957d67a' 
  AND token = 'vHNwhKTVFfymoxHGYPiWc9ebTLb/qG8aqk6Au0IaMe0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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