SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2cacaa50dfdea66aa46be227be880049760c9386c57ed2a315caaca6d9dfe798' 
  AND token = 'LZV/XfjshPfgohboWDTPJ6eiMLONgEJAohZxSO6E7Ag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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