SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cab82dec968e95fdbfaf3c9e04d6011ebdad2a60c78c5a5651ba490438b18bc' 
  AND token = '6NZ+fKZJUXovl5n7Oftj76lbNcSTtSXXegJxWcFdVhE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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