SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cc80c3687d79b1572cd912a506fd47a1d605202ce07b99de8e90cc495010664' 
  AND token = 'CNGFN59xISrgIqQNCt3+ISVsQvLmM5/qqw4YcRwMgWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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