SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afe1e27a3e9d65646a8a6bf996bfc42dfda7d1303fa2a28ffc471dfcf8ecb6bb' 
  AND token = '6HuW8ColZTdsGxyiPe3Zpl9Jo9XFspjO2aplrgESrbI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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