SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a42f89f0a64971338c08cc2cff982d365fc64aa380b5aa374c28864c90e5eb45' 
  AND token = 'KVK04ur+bWfsEm/Cnhk/vVjcGX5C12FpuQMe9QWHuwE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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