SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac13b6dcff3cfc2d5a3bac852f3f92efd24e6a6df43596d340d701170d146b85' 
  AND token = 'rx4Y+SxN3KXEha0SlArPfrZYbidGwnON+f+BohpL9X0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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