SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '750a9c74b8fc8a3145639625b6331375535c00bf6b437735c804046e924fdbcd' 
  AND token = 'ngqvv2ayu2BxfwQheHKYzwyap6p4VjNKr0JiqzgaQuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}