SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '300b118e6cfaeb455046f29809d37ef59d4737bbf908dbbee1633daadfa07827' 
  AND token = 'OjjqAfZNS66cqitBH4Dio0N82BM5qhsNao/zF+Nlgmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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