SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'df703531bdb16a241a3b9ffe84c98523334dffc75be3a5922c7a10f7bc7f71a2' 
  AND token = 'i146XnnVhYuumYP9U80+GG0voacdkMIS1vNSIcMEaUs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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