SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '567dec0ba50d1ada91c58539436aa2498f471d35e4528955b82e52234828ecd7' 
  AND token = 'era2yGY5RDi6WJMTCNuSMvcLSldzjTKtVRhX8oaoSvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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