SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '610b83e0a56e98b27bfb2d34770549995f83f54f723e5da4b360674b64aefbf8' 
  AND token = 'RwxtQdKYdJl/Bu+1cg2HnqqRx/Z8/AMlrvi2eZAcxPM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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