SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '582600220d4dc7dbceb7ef490bc6b7cdfaee1bcbc7a399301dedd0679e099fcc' 
  AND token = 'Rwu2j2LU+lvYQhsOmfhiGPQfowyzsvGuRUqRNJyVDIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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