SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6a76e4f0f5fb247f345d8e2bea1d1c06fc6cc5565692570c5f847339566d8f1' 
  AND token = 'dafZn35zz8uQyCpz7Qmm3Aevm/qqVmzs97cef1v9WrE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}