SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e78b368a7537bed663497975b8e10c5dcabc8054a930ea4c8f169016c137505e' 
  AND token = 'R7Y2JwKA+rVD5G4RpXbkcLbsvEVgPmdtVeTD5bsSrgM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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