SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '792da09ca78c1981d705f8c53ab1ec4a25770b2f3ed73843494e133cf9145386' 
  AND token = 'K1JPDv6WWcmgleLR91cmY8laRNqji8O/7m0ltGsJiEc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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