SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dac4c673a41457a827a9d7bd11651af98b51515f29c32d5a7939e295abb4d56a' 
  AND token = 'OHjCXnuD8nY6V1TG9g1/qlTfBprnM7Xc4ZPMcUUyIRs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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