SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '523fe77086b72abdbec0e8c2f370d323dad53d19ef211f9c9a3644f50f003a1e' 
  AND token = 'klXXNkKj6o1LWQWvlUta+zELW8e7J4uVPDdanuCdyyQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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