SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd383c885c6270e37c3b25bfa3f4b6d674af2cdfd2c20489e5a8c9a88dde60503' 
  AND token = 'TxXC47PwQBBxRNAI+I332vWREnFYQJBqxpVrDfClGhk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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