SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2e994d8091ff7b4aef47938b1b88beefeb413d3377f456439cefeaba59cd37e7' 
  AND token = '7extTLzrQazBPjDb7Knv+Bl0EnCNMife8wid1kyLuw0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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