SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19729b1f3bbfa2bfb7eff8c97f5ce86a706dc14fc46d893b14198b29e6e03b13' 
  AND token = 'JiavF+tGxj4+B721hlULRHpqBOPXOYR9BzOu2YuYf3k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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