SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8f4ea53fcea9d45f0aeefac518fc7731563a377c4a9916e7ad652b3d7601da5' 
  AND token = 'BP7pGwCGhxJYxeCcHRXPb4Xoy+NY13TZqR53xEAPs84=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}