SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d48eb2e2ad5fe1b1273703ccbde791646f917c42efda77122a1093e05c0dd15' 
  AND token = 'gldin7jStQyua6Jb+hTuTxycFfUNk8fVnDQt/Epzj+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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