SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3557ecdf8473563b123c01830b91fb37f8e744e300774a418e03fd8588ecc3e0' 
  AND token = 'YZqm8Y5kzA59wy41lq49DZWzC4YnPJtxxpovh43Nc0A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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