SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca92c8a0862d52b6672bd58e8afb6f1b78cce9f975f4045121f360e5e2321c64' 
  AND token = 'fdIQVJFCUaZb6gjnawBIouWz9kQBC+R38TPFR8Wt5Uo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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