SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f71dee39530c042aa49c3f26e51f5fb533c3d4386c121dfb0eaa2f5dcc16c65' 
  AND token = 'jTrY8EM5n2zaKEkhRCGlcZcYCP6KGEOXsvHgQOMsbnw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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