SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db0fd57560daa2900e913cce3e319baf5dcd2b704e0aaee7cc844235b9a0d26d' 
  AND token = 'snAKnW2kbxWDpM1Dp/gSd9FwVd8FkOTJ007Be5KahZU=' 
  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"
    }
  }
}