SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b39a423cb2685b5f09032dbd337471d751595b6ddfb9eff6dc2ac1e7b0c78ff3' 
  AND token = 'TQZvI2nvXzvBay+eev4GZ94Y9dnwqHNIGcXq9/IvNGs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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