SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b18b862da86ebec16137281aea2f05a5d6bb715b5b7cfd3bebb81c23435035b' 
  AND token = 'YDBKO+xw6JdGMXZx3clTrVteVvGwU/AqtdWpA2//S0w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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