SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '13ce559616f528c07327e7aa3ac0edef214910d17f0f798a177fa881214e8471' 
  AND token = 'zStKdFLVFN2iuuDH9ADATiMQE1be62d+pSuvDRVkfas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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