SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d35d262bab91856889ce2aef988fdc0378f6a743f2fa01ceb6b2d27fca4d5af' 
  AND token = 'eZMjC8kptk/kuI+8cpV5hisDtgB5aWQjNsc2E+fu0so=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}