SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b4f336f9711b80ff9f82d7ffe5d40b2d9c3750aa2b7ddcbae7d161a0104db615' 
  AND token = 'YwY+zkvs3UXdh3QKlkPCUxU9ih29IzsddTb8UD2YK6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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