SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fde922144a9dd2c58b13dfd8998a4d4d814510d4f3e43ef6753241c7e5040b6c' 
  AND token = 'yHQ8MUWV6DRP64yz8k7gAgJOuxYwpVZGlj/fzJuRHpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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