SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d52f3aa4acb4e70444c05f8cfc62d5e03557866304603b48f9d649ff7abc0f8' 
  AND token = 'c451VPmYmfZRxhEfyFNv7QKwgIhpDacbWr6D51z4GqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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