SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9203f0b2f002805414cc6869508ed1638989ef5508c93d53ea0a31372073ac9' 
  AND token = 'N3/xqdw0r6of+MDJtarstGf3AErKGBL9ZqHNF732qV8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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