SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4f818d2b60b851d19f2f5b258ffb3a8117f4ac8e7ce2de9659e1a7cfa2139cec' 
  AND token = 'TmxqLAFcHobfpl6L+fcCdDIhUfZ0lr5VrREfoV9PttA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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