SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f0d3305d51e28e5a22c78390d9b67146e44c7cb2bbc5d6fe488eb3ccc5e4e84' 
  AND token = 'jItrY728MbDS4hFfNTBeplIxeCi58TozYE+k/1vw9vQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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