SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a5a292920e2bc00057a4c1c1945c42ae5aa175911a75f349e99bc544f08e8311' 
  AND token = 'uGRImbEMs/iy3rG3uSP/qQjdtWvAQP4ldPIt6e21guw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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