SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ec4b82e830d134185cd72d40aa22c1bdbb2c13d87dad03842c6529abf4af7bec' 
  AND token = 'xvlRDuaKTvIikbXiCtrw6eV3D1AJt/maspdO/bFHtAg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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