SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26143f10e191c0c5f6bfb051d627cd0882a7d14246e42707f021d87cabe1c130' 
  AND token = '4z3akkvqzfopz1VngRyr+JurpPgg2TjvY4YFzMCSB+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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