SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2f9a4ec4e398c9c3fa2072497f4cea046bd2b06b556902078aaadcafa6f7959' 
  AND token = 'BdPNApFl5gWjkOdZhrChTfTlUCm/aiMd8LsMNUheBTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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