SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7877483934edd173ce9954af2df6b3607506d64b473b15e3a5ac042b2cf5aacd' 
  AND token = 'ooBOnPgSBshzLWWvDXevms80P+dG8fPlYBPuJk97FJ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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