SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15a353b187a847b3e0b46c38a24ee4a7355aef444b0b219cc465146e7a29d148' 
  AND token = 'jP981XDiKoUSi/jM+vnsSCGohT+/5pHTFa46PqU7inA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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