SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6f28c8c869c678d0b1fcd3247558db547ca8ca65746823402cdfd491884a858e' 
  AND token = 'xOzTR8cPekqNY38v1Mof/FxViCdl2cutBgPOfa/xunM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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