SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23219160480ffe23ec3f533794a6125c1c19bf2470155c79e223cd51db5783c8' 
  AND token = '4vNVPqovxfoB9g06NNqioXnfqYLrQyjYMgLO7zw5Vh4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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