SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e9f2d1c33ae2cd8006d31b94de78c66a702c80be91432f41894065583818eba' 
  AND token = 'JgwJtdb8TK+FhTM+loIcfsWSAcDp80UrHw5d8lgY8ts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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