SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ce81302317ef106808244e2b427f888071070a3ad6e670e56b7559dfae6f80d' 
  AND token = 'qYFG/ODNdJygN5SFsTCzArwkO56hoHAQWoxYKdSVx2c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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