SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c8dffdab9a612110215ae496aa88eb6ef20ee6d080db98e695323ebf337624a' 
  AND token = 'm+mlRf6s9YuQZceYXpn/Qq8NgnR0LDJzECKzRZEGLNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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