SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3d9b1e292f8e4b02f78243167a7469fac276ef98c1557ae293a92b469b6cda9' 
  AND token = 'jVw/bamSFOH9wWYkk00n+si7EMJIQlcYjgHGfZ0oV6w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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