SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72ac53aebd0fab1c10f92da97ce794af272953ccc8351cb81642b5b942466a73' 
  AND token = 'lehIiKat5ply2BghxFz1slGhA+DYE6IEp9i/ujlH6ZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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