SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e114b3bf821786bf3c747c0e68ad1041390f2c05ab162d7d3e7ada7ae40589b' 
  AND token = '+9LNxua3sAflgBR0UDDqAZvzu9vCjtVw8JKfVaVMEbA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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