SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9ff6961231d224d1b5a8ba8fd1525c1e2e4b0af979d741d6f66696e183bb2cc' 
  AND token = 'PRKZS+K2yp26VR6rko+VwLX2xe8PoScRAY5s7ORiQnY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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