SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3768fcc83362710ccfa4c1d00c27699ed3cbbd52cdc40e504f84296c3fc17c1a' 
  AND token = 'FHUFm87vR9inVRsHNvcJkDMHmSPKkzbxfzpXSFfDB3I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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